Machine for bending bars and the like



Feb. 20, 1945. R. M. SHAW, JR 2,369,923

MACHINE FOR BENDING BARS AND THE LIKE Filed Feb; 27, 1943 ATTORNEYS.

Patented Feb. 20, 1945 I UNITED STATES PATENT OFFICE MACHINE FOR BENDING BARS AND THE LIKE Ralph M. Shaw, 'Jr., Edgewater Park, N J.

Application February 27, 1943, Serial No. 477,345 (01. 153-46) 2 Claims.

This invention relates to methods of bending relation of parts of the machine after pletionof a bending operation.

Fig; 3' is a fragmentary sectional view taken as indicated by the angled arrows I I I-- III in Fig. 2

the com- I and drawn to a larger scale.

Fig. 4 is a detail sectional view taken as indicated by the angled arrows IV-IVin Figs. l and Y 3 and likewise drawn to larger scale.

is always a minimum. Unless restrained, bending always takes place about this axis regardless of the direction in which thebending force is applied. In structural angles and Z-bars this is commonly known as the 2+2 axis. When not restrained, a piece upon which the bending force is applied along the first mentioned or the 1-1 axis, but is permitted to bend along the 2-2 axis, results in a section the plane of the heel of which is non-coincidental with the heel plane of the unbent section, the piece being thus distorted and weakened at the bend.

My invention is directed toward overcoming the foregoing drawback, that is to say, toward making possible the bending of bars of different cross sections in one direction or another to the exclusion of any cross sectional deformation or weakening in any part of, the finished product.

This desideratum I attain in practice as hereinafter more fully disclosed, through provision of an improved machine which performs the step of fore-distorting the opposite end portions of the bars beyond the intermediate regions at which the bends are'to be made in order that the tendency toward distortion at such intermediate regions is automatically compensated for during the bending, withincidental restoration of said end portions to their original condition; and through the further provision of a machine or apparatus having improved appurtenances whereby the pre-distorted end portions of the bars are held in restraint with capacity, however, to gradually assume their original relationship with respect to each other and the intermediate portions I Fig. 5 is a view corresponding to Fig. 3 with the machine arranged for-bending angle bars toeoutward; and

Fig. 6 is a detail sectional View taken as indicated by the angled arrows VI--VI in Fig. 5.

The bending machine herein illustrated isgen- "erally similar to the one disclosed in'U. S. Patent No. 2,266,912 granted to me on December 23,

manual means or by power, as desired. Rigidly secured by bolts 5 to the disc 2 at the center is a round spool-like die member 6 whereof the periphery, see Fig. 3, is profiled to snugly receive and support the horizontal flange of the angle bar B which is to bebent, and to provide a buttressing surface for the upright flange of such bar. Cooperative with the die member 6 is an opposing complemental die element 1 which fits between the upper and lower flanges of said die member, and which is held against the outer face of the upright flange of the angle bar B by a roller 8, said roller being adjustable in a radial guide 9 on the disc 2 in the same manner as the corresponding roller in the patent hereinbefore referred to. Attached by bolts ID to the bed I and overlying the disc 2, is an inwardly projecting segmental plate bracket II that supports a holder l2 which is of right-angle cross sectional configuration as shown in Fig. 4 and which is formed with a hook it to engage over the top edge of the vertical flange of one end portion of the bar B. Extending laterally from the holder l2 are studs l4 which fit into socket holes in one edge of the segmental plate H. In turn mounted on the disc 2 is a generally similar hooked holder l6 which has pendent studs ll fitting socket holes in said disc. v

To bend the angle bar B toe-inwards, in accordance with my invention, the procedure is as follows: The bar is placed in the machine as shown in Fig. l with its mid portion, i. e., that portion at which the bend is to be made, engaged in the periphery of the die member 6. The cooperative die element 1 is then slid into the inportions of said bar incidentally engaged in the hooked stops l2 and I6. Thereupon, by means of a lever or other suitable tool, the end portions of the bar B are torsionally deformed or twisted relative to the intermediate portion, both in the same direction, to an angular position such as shown in Fig. 4. With the foregoing preparation, the disc 2 is rotated in the direction of the arrow in Fig. 1 and the right-hand end portion of the bar caused to swing around the die member 6 under the pushing action of the complemental die element 1. During the bending, the pre-deformed end portions of the bar are held in restraint by the holders l2 and IS with capacity however to turn and at the same time shift longitudinally therein, the twists being progressively absorbed in compensating for the strains induced in the metal of the bar at the region of bending. As a consequence, at the completion of the operation when the bar has been bent to the desired extent, its end portions will have assumed their original aligned relationship with the bent portion thereof, while the cross section of the latter portion will be maintained as a true right-angle. The degree of twist originally placed in the bar ends will of course have to be varied in practice in accordance with the length of the bar and the extent to which the bar is to be bent, and also in accordance with the cross sectional dimensions of the bar material. If found to be more convenient in practice, the end pre-twisting may be done before the bar is placed in the machine. 1

In Fig. 5 the.centra1 die member 6a. is shaped to receive within its peripheral groove, an angle bar B toe-outward with the vertical web thereof backed by the mid portion of said member, and the horizontal flange thereof supported from beneath substantially throughout its width. The cooperative die element Ia, on the other hand, snugly engages between the upright flange of the central die member 6a and the top surface of the horizontal flange of the bar B. The holders used with the machine as arranged in Fig. 5 are shaped as instanced in Fig. 6, and before bending, the end portions of the bar are twisted in the direction shown in the last mentioned illustration. The bending procedure here is exactly the same as described in connection with Figs. 1-3, incident to which the tendency toward distortion at the region of bending is compensated for by the pie-twisting of the bar ends in the indicated direction.

While for the purposes of exemplification herein, I have shown and described the bending of angle bars with my improved machine, my'invention is not confined to operation on such shapes. since through suitable modifications within the scope of the appended claims, bars of other unsymmetrical cross sectional configurations can be as readily bent without sacrifice of any of the advantages hereinbefore pointed out.

Having thus described my invention, I claim:

1. A machine for bending bars of angular cross section, previously prepared by having their ends twisted relative to the intermediate portions at which the bends are to be made, comprising a pair of cooperative die members whereof one is spool-like and stationary while the other is retatively movable thereabout, said members jointly providing a confining interval accurately conformative with the cross section of the bar; and a pair of hold-down elements associated with the die members each embodying a hook, one of said elements being rigidly mounted and the other radially adjustable and respectively engagin the pre-twisted end portions of the bar to be bent, so that incidental to the bending operation all portions of said bar will be turned back into normal position, and be free from twist.

2. The invention according to claim 1, in which the stationary spool-like die member has a circumferential groove profiled to receive the vertical and horizontal legs of the angle bar; in which the roller die member engages the back face of the vertical flange of the angle bar to confine the cross section of the latter; and in which the holddown elements have the form of angular clips with their vertical legs turned inwardly and downwardly to hook over the top edges of the bar ends.

RALPH M. SHAW, JR. 

